32768 color dual Shifter ST mod - schematics lost?

[sporniket]

It should -hopefully- arrive by next week.

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[sporniket]

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The work of this month...

Next is putting some pins and test the fitting inside the can, then checking the traces are not broken nor shorted...

[mrbombermillzy]

That looks great.

It seems Ive been lucky as from what I can see and looking in my MST, the board is facing away from the PSU, so there should be plenty of room, bar the odd cap or two and it should fit without changing anything.

@sporniket Have you managed to get hold of any shifters yet?

[sporniket]

That looks great.

It seems Ive been lucky as from what I can see and looking in my MST, the board is facing away from the PSU, so there should be plenty of room, bar the odd cap or two and it should fit without changing anything.

Indeed, a fortunate coincidence

@sporniket Have you managed to get hold of any shifters yet?

Obviously, I have the shifter from the donor STf, a CO25914-38A, I can lend it to you if you need. I have no other shifter.

I could try to fit it inside the can, and it does fit.

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2022-02-02--shoe-fitting-02-it-fits.jpg (184.88 KiB) Viewed 3474 times

So now some trace checking, and I have to prepare an order at mouser... Stay tuned.

[mrbombermillzy]

Great.

I currently have the IMP shifter in the Mega, but have managed to aquire an STF with a CO25914-38A (non working machine, but I hope the shifter is ok!!). Its very lucky (well, for me) that they are both socketed.

Im more than happy for you to borrow the matching shifter if you want to try it out? Otherwise, yes if you could lend me your shifter, that would be awesome!

On a different note...

I was thinking, theoretically at least, theres the possibility of having a 32 colour palette (2x16 word locations in RAM) if there was some memory mapped location that could be used for the 2nd shifters palette addresses. Is there a way of mapping the unused shifter palette to some e.g. reserved/unused memory locations? (The holy grail would be to make the palette relocatable )

[sporniket]

Im more than happy for you to borrow the matching shifter if you want to try it out? Otherwise, yes if you could lend me your shifter, that would be awesome!

I have no machine to test, so I will lend you the shifter for the time being.

On a different note...

I was thinking, theoretically at least, theres the possibility of having a 32 colour palette (2x16 word locations in RAM) if there was some memory mapped location that could be used for the 2nd shifters palette addresses. Is there a way of mapping the unused shifter palette to some e.g. reserved/unused memory locations? (The holy grail would be to make the palette relocatable )

Returning to the original colorspace (rgb333) one could imagine to use the bit 15 of a palette to target the main shifter (0) or the secondary shifter(1). The problem lies in the fact that whatever we do, there will only be 4 bitplanes fed to the shifters, so only 16 colors max. It requires to hack the MMU and the GLUE altogether. Anyway it is beyond my capabilities, if there is a solution.

[SophieRose]

Would love to give one of these a go in my mega

[HigashiJun]

Would love to give one of these a go in my mega

Yup, I had the same idea.

There is plenty of room in a Mega, so should fit without any problem.

[sporniket]

Would love to give one of these a go in my mega

Yup, I had the same idea.

There is plenty of room in a Mega, so should fit without any problem.

I take note of your interest. I prefer to wait to have some results first, though.

[mrbombermillzy]

@HigashiJun and @SophieRose ...
You two had better start collecting shifters then. I'm not even sure it's viable to produce this board in any sort of volume with the lack of the earlier ST shifters around.

Absolutely none on ebay, or Exxos' store. (I don't suppose trying to get a batch from Brad would help his anti-reseller paranoia, but that might be an option).

I've had to pick up a shabby STF machine that didn't work (STs aren't cheap anymore) and PRAY that the previous owner didn't fry the machine, or drop it in the bath or whatever, so at least the shifter works.